1. Field of the Invention
The present invention relates to voice messaging systems, and more particularly, to a method for integrating a voice messaging system card (VxC) with a PBX.
2. Prior Art
The VXII Voice Mail System developed by Executone Information Systems and implemented in a line of PBX systems (i.e., integrated digital system (IDS)), has the capability of exchanging control signals through both in-band signals using DTMF tones, and through the use of asynchronous RS-232 communications. While the RS-232 signaling does not replace all of the functionality of the in-band signaling, the use of the RS-232 signaling eliminates the requirement that the IDS provide DTMF receivers for each of the serial line interface (SLI) ports connected to the VXII.
With the development of the VxC card and its first uses, it requires the use of an IDS serial port and an external cable connecting the VxC to the IDS CPU. Additionally, an external monitor and keyboard are required for the programming and monitoring of the operation of the VxC. All of these additional components increase the cost of providing voice mail to low end systems.
The voice card operates on a DOS platform, and generally uses a memory manager for efficiently using memory locations contained within the operating environment. QEMM is one type of memory manager that has been used. However, its use requires royalty payments to Quarter Deck, and is therefore not desirable in the present invention.
In previous implementations of the VxC card, a dual port RAM of the card acted as if it were an OPX card, and the RS-232 connector on the VxC card was connected to a serial port on the IDS. A keyboard and monitor were attached to the keyboard and VGA connectors respectively. With this configuration, the VxC card could operate within an existing IDS without requiring any code changes on the IDS.